Water monitors, also referred to as “water turrets,” “water cannons,” “fire-fighting monitors,” “fluid monitors,” “monitors” and the like are used to manually or automatically distribute high-pressure streams of foam, water, water-based foam and fire retardants over an area determined by the amount of fluid pressure, the angle of elevation of the water monitor, its arc of azimuthal oscillation, its speed of azimuthal oscillation and its pattern of azimuthal oscillation. Water monitors are primarily used to extinguish fire hazards, although other uses may include fire prevention, irrigation, crowd control, and water-cooling of objects.
Water monitors are often configured with a fluid input portion that is fixed, stationary or otherwise non-moving (hereafter generally “stationary” herein) with respect to a fluid output portion. The fluid output portion is usually movable and is positionable to a select azimuth and/or elevation. Such water monitors typically utilize one or more electric motors and reduction-gear assemblies (hereafter “gearboxes”) to convert a relatively high-speed, low-torque output of the motors to a relatively low-speed, higher-torque force for moving a fluid outlet of the water monitor to a select position.
Positionable water monitors are usually configured with ball bearings interposed between the stationary portion and the movable fluid outlet elbow to reduce rotational friction between these components and to support radial and axial loads exerted upon the movable portion. A pair of races are utilized to contain a plurality of balls and to transmit the loads through the balls, one race being formed in the stationary portion and a facially adjacent race being formed in the rotatable portion. As the race in the rotatable portion moves it causes the balls to rotate as well. Because the balls are rolling they have a lower coefficient of friction than if two flat surfaces were rotating upon each other.
A significant drawback of this arrangement is that fluids flowing through the water monitor at high pressure exert a separating force upon the bearings. This separating force adds to the mechanical load imposed upon the aforementioned electric motors and gearboxes, and can result in excess component wear and reduced service life for these components.
Utilizing electric motors and gearboxes rated for higher loads may be utilized to counter this problem, but such an approach requires components that are more expensive, physically larger, and have greater weight when compared to electric motors and gearboxes designed for smaller loads.